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US 4,367,948 AGranted
Surface potential electrometer and image forming apparatus using the same
AssigneeCanon Kabushiki Kaisha
InventorKoji Suzuki
Life of this patent
Estimating the term…
Abstract
The surface potential electrometer includes a reciprocating chopper, a measuring electrode on which a voltage is induced which is associated with the surface potential of a member to be measured, a shield member for shielding the measuring electrode and the chopper from electric field emanating from the member to be measured, and a driver for driving the chopper, thereby detecting the surface potential of the member in the form of an AC signal. The shield member is provided with an aperture for guiding the electric field emanating from the member to the measuring electrode.
Claims59
An image forming apparatus, comprising:
- a recording member;
- means for forming an electrostatic latent image on said recording member;
- means for developing said electrostatic latent image;
- detecting means for detecting the surface potential of said recording member;
- control means for controlling said latent image forming means or developing means in response to the output from said detecting means;
- support means for supporting said recording member and said surface potential detecting means;
- and
- connecting means for electrically connecting said detecting means and said control means, said connecting means being removably mounted on said support means, and the electrical connection between said detecting means and said control means being made or broken according to whether said detecting means is attached to or detached from said supporting means.
5 more elements
A surface potential electrometer, comprising:
- a measuring electrode on which is induced a voltage corresponding to the surface potential of a member to be measured;
- chopping means for intermittently interrupting the electric field between said measuring electrode and said member to be measured for detecting said surface potential by said measuring electrode as an AC signal;
- a conductive member for shielding said measuring electrode from the electric field emanating from said member to be measured;
- and
- regenerating means coupled between said electrode and said conductive member for converting said AC signal into a DC signal, and for supplying said DC signal to said conductive member thereby enabling the detection of the surface potential without the effect of change in the distance between said member to be measured and said electrode.
2 more elements
A surface potential electrometer comprising:
- a measuring electrode on which a voltage is induced corresponding to the surface potential of a member to be measured;
- a mechanism for causing said electrode to respond intermittently to the electric field from said member to be measured;
- a driving circuit for driving said mechanisn so that said electrode detects the surface potential of said member as an AC signal;
- a conductive member for shielding said electrode from the electric field emanating from said member to be measured;
- a AC-DC converter for converting said AC signal signal into a DC voltage substantially equal to the surface potential of said member;
- means for applying the output voltage of said converter to said conductive member;
- and
- a voltage source having a reference output voltage which varies in accordance with the variation of the surface potential of said member to be measured.
5 more elements
A surface potential electrometer comprising:
- a measuring electrode on which a voltage is induced corresponding to the surface potential of a member to be measured;
- a mechanism for causing said electrode to respond intermittently to the electric field from said member to be measured;
- a driving circuit for driving said mechanism so that said electrode detects the surface potential of said member as an AC signal;
- a conductive member for shielding said electrode from the electric field emanating from said member to be measured;
- a pre-amplifier circuit for amplifying said AC signal;
- a regenerating circuit for converting the output signal of said pre-amplifier circuit into a DC voltage substantially equal to the surface potential to be measured;
- means for applying the output voltage of said regenerating means to said conductive member;
- means for coupling said pre-amplifier with said regenerating circuit for providing reference potentials thereto which are different from each other;
- means for coupling the reference potential of said pre-amplifier circuit with the input of said regenerating circuit;
- and
- means defining the reference potential of said regenerating circuit as a measuring reference potential of the surface potential of the member to be measured.
8 more elements
An image forming apparatus comprising:
- process means for forming an electrostatic latent image on a recording member and for developing said latent image;
- a measuring electrode on which a voltage is induced corresponding to the surface potential of a member to be measured;
- a mechanism for causing said electrode to respond intermittently to the electric field from said member to be measured;
- a driving circuit for driving said mechanism so that said electrode detects the surface potential of said member as an AC signal;
- a conductive member for shielding said electrode from the electric field emanating from said member to be measured, and for housing said electrode;
- a AC-DC converter for converting said AC signal signal into a DC voltage substantially equal to the surface potential of said member;
- means for applying the output voltage of said converter to said conductive member;
- and
- a voltage source having a reference output voltage which varies in accordance with the variation of the surface potential of said member to be measured.
6 more elements
An image forming apparatus comprising:
- process means for forming an electrostatic latent image on a recording member and for developing said latent image;
- a measuring electrode on which a voltage is induced corresponding to the surface potential of a member to be measured;
- a mechanism for causing said electrode to respond intermittently to the electric field from said member to be measured;
- a driving circuit for driving said mechanism so that said electrode detects the surface potential of said member as an AC signal;
- a pre-amplifier circuit for amplifying said AC signal;
- a regenerating circuit for converting the output signal of said pre-amplifier circuit into a DC voltage signal;
- a conductive member for shielding said electrode from the electric field emanating from said member to be measured, and for housing said electrode and said pre-amplifier circuit;
- means for applying the output voltage of said regenerating means to said conductive housing;
- means for coupling said pre-amplifier with said regenerating circuit for providing reference potentials thereto which are different from each other;
- means for coupling the reference potential of said pre-amplifier circuit with the input of said regenerating circuit;
- and
- means for defining the reference potential of said regenerating circuit as a ground potential.
9 more elements
Dependencies are inferred from the claim text.